4．下列代码段的输出结果是（　　）。

int a[10] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
for (int i = 0, j = 9; i < j; i++, j--)
{
    int t = a[i];
    a[i] = a[j];
    a[j] = t;
}
for (int i = 0; i < 10; i++)
cout << a[i] << " ";